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1.
J Mater Chem B ; 12(10): 2587-2593, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38363549

RESUMO

Due to increasing bacterial resistance to disinfectants, there is an urgent need for new therapeutic agents and strategies to effectively inhibit bacteria. Accordingly, we have designed and synthesized a novel crown ether known as C7Te, and its oxidized form C7TeO. These compounds have demonstrated antibacterial effectiveness against Gram-negative E. coli (BL21). Notably, C7Te has the capability to enhance the inhibition of E. coli and the prevention of biofilm formation by H2O2 through a redox response. It can also effectively disrupt preformed E. coli biofilms by penetrating biofilm barriers effectively. Additionally, computer modeling of the bacterial cell membrane using nanodiscs composed of phospholipids and encircled amphipathic proteins with helical belts has revealed that C7Te can insert into and interact with phospholipids and proteins. This interaction results in the disruption of the bacterial cell membrane leading to bacterial cell death. The utilization of redox-responsive crown ethers to augment the antibacterial capabilities of H2O2-based disinfectants represents a novel approach to supramolecular bacterial inhibition.


Assuntos
Éteres de Coroa , Desinfetantes , Escherichia coli , Éteres de Coroa/farmacologia , Peróxido de Hidrogênio/farmacologia , Antibacterianos/farmacologia , Bactérias , Oxirredução , Desinfetantes/farmacologia
2.
J Chromatogr A ; 1719: 464751, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38387151

RESUMO

Two new extraction chromatographic resins (ECRs) were prepared by impregnating two exotic diglycolamide (DGA) ligands (having three or four DGA moieties tethered to aza-crown ether scaffolds) dissolved in an ionic liquid onto an inert solid support. A room temperature ionic liquid (RTIL) was used for enhancing the performance of the ECRs. The ECR containing triaza-9-crown-3 functionalized with three DGA moieties (TAM-3-DGA), and tetraaza-12-crown-4 tethered with four DGA arms (TAM-4-DGA) were evaluated for the separation of Am3+ and Pu4+from nitric acid solutions. The resin capacity for Eu3+ was 9.52 mg/g and 7.24 mg/g for TAM-3-DGA and TAM-4-DGA resins, respectively. Similarly, the resin capacity for Pu4+was 7.44 mg/g and 5.72 mg/g for TAM-3-DGA and TAM-4-DGA resins, respectively. These maximum loading values corresponded to the formation of a 1:1 metal/ligand complex for the Eu3+ ion and a 1:2 metal/ligand complex for the Pu4+ ion. The sorption of Eu3+and Pu4+on the resins followed a chemisorption phenomenon on both resins. The sorbed Eu3+and Pu4+ions from the resin phase could be efficiently desorbed with complexing ligands such as guanidine carbonate/HEDTA and oxalic acid, respectively.


Assuntos
Elementos da Série Actinoide , Complexos de Coordenação , Éteres de Coroa , Líquidos Iônicos , Líquidos Iônicos/química , Ligantes , Elementos da Série Actinoide/química , Cromatografia , Íons
3.
Anal Chem ; 96(6): 2651-2657, 2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38306178

RESUMO

In vivo sensing of the dynamics of ions with high selectivity is essential for gaining molecular insights into numerous physiological and pathological processes. In this work, we report an ion-selective micropipette sensor (ISMS) through the integration of functional crown ether-encapsulated metal-organic frameworks (MOFs) synthesized in situ within the micropipette tip. The ISMS features distinctive sodium ion (Na+) conduction and high selectivity toward Na+ sensing. The selectivity is attributed to the synergistic effects of subnanoconfined space and the specific coordination of 18-crown-6 toward potassium ions (K+), which largely increase the steric hindrance and transport resistance for K+ to pass through the ISMS. Furthermore, the ISMS exhibits high stability and sensitivity, facilitating real-time monitoring of Na+ dynamics in the living rat brain during spreading of the depression events process. In light of the diversity of crown ethers and MOFs, we believe this study paves the way for a nanofluidic platform for in vivo sensing and neuromorphic electrochemical sensing.


Assuntos
Éteres de Coroa , Estruturas Metalorgânicas , Éteres de Coroa/química , Sódio/química , Íons/química , Potássio/química
4.
Chirality ; 36(3): e23656, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38408846

RESUMO

Considering the substantial significance of chiral biomolecules, such as amino acids, in our daily routines, we performed chiral recognition and discrimination of tyrosine (Tyr) enantiomers on (-)-(18-crown-6)-2,3,11,12-tetracarboxylic acid [(-)-18-C-6-TA] as crown-ether type chiral selector (CS) by nuclear magnetic resonance (NMR) spectroscopy and docking simulations. In this study, successful discrimination of the enantiomers of Tyr was achieved, as evidenced by the proton chemical shift differences (ΔΔδ) of Tyr enantiomers observed in the 1 H NMR spectra with (-)-18-C-6-TA CS. We compared the results of these two techniques with the findings obtained from high performance liquid chromatography (HPLC) investigations. In both NMR and HPLC experimental and docking simulation studies, a stronger interaction between the L-Tyr enantiomer with (-)-18-C-6-TA CS than the D-Tyr was consistently observed. Also, the binding energy differences (ΔΔEL-D ) found in simulation data that correspond to enantioselectivity aligned well with the NMR experimental result.


Assuntos
Éteres de Coroa , Tirosina , Estereoisomerismo , Éteres de Coroa/química , Espectroscopia de Ressonância Magnética/métodos
5.
Chemosphere ; 352: 141363, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38346508

RESUMO

Adsorptive separation membranes are widely utilized for the removal of toxic dyeing pollutants from dyeing wastewater. However, developing novel adsorption membranes with large adsorption capacities and enhanced adsorption performance for dyes in actual wastewater poses a significant challenge. This study focuses on the fabrication of crown ether-containing copolymer porous membrane (CRPM) and investigation of the adsorption performance of dyes from aqueous solutions. The morphology structure and pore size distribution revealed that the membrane was endowed with rich micropores and hierarchical porous structures. Three typical cationic dyes (MB, RhB, CV) and an anionic dye (MO) were selected to evaluate the adsorption behavior. The results of adsorption isotherms and kinetics demonstrated that the adsorption data could be well-fitted using the Freundlich and pseudo-first-order kinetic models, the thermodynamic parameters revealed that the adsorption process of dyes on CRPM is a spontaneous endothermic reaction. The membrane exhibited excellent adsorption performance for cationic dyes, with RhB displaying a higher maximum adsorption capacity than previously reported porous membranes. Notably, dynamic adsorption-desorption filtration demonstrated a rapid removal efficiency, with RhB, MB, and CV achieving removal rates of 99.09%, 98.63%, and 99.14% respectively, after five cycles. The filtration volume of the CRPM membrane was 2.4-fold greater than that of a traditional PVDF membrane when applied to actual dyeing wastewater. DFT theoretical calculations were employed to elucidate the adsorption mechanism. These calculations confirmed the significant roles of electrostatic interactions, H-bonds and π-π interactions in facilitating the high-efficiency adsorption of cationic dyes. These findings highlight the potential of the crown ether-containing copolymer as a promising material for adsorption separation membranes in the treatment of dyeing wastewater.


Assuntos
Éteres de Coroa , Poluentes Químicos da Água , Corantes/química , Águas Residuárias , Éter , Adsorção , Porosidade , Poluentes Químicos da Água/análise , Etil-Éteres , Cátions , Cinética , Polímeros
6.
Medicine (Baltimore) ; 103(4): e36214, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38277579

RESUMO

RATIONALE: Radical surgery offers the best chance of cure, it is critical to expand surgery opportunities for patients with early-stage lung cancer to prolong overall survival. However, evidence is still limited regarding the application of neoadjuvant therapy with EGFR-tyrosine kinase. PATIENT: The patient reported here was a 53-year-old woman with right lower lung adenosquamous carcinoma. DIAGNOSES: The lung cancer was staged as T3N1M0. Tumor genotype disclosed EGFR Exon19 c.2235-2249de p.E746-A750del. INTERVENTION: After neoadjuvant treatment with icotinib, she underwent thoracotomy and achieved pathological complete response. OUTCOMES: She is currently receiving adjuvant icotinib therapy without recurrence or metastasis during 18-month follow-up. LESSONS: Our case indicated that the feasibility of neoadjuvant icotinib in EGFR-mutant lung adenosquamous carcinoma.


Assuntos
Carcinoma Adenoescamoso , Carcinoma Pulmonar de Células não Pequenas , Éteres de Coroa , Neoplasias Pulmonares , Quinazolinas , Feminino , Humanos , Pessoa de Meia-Idade , Carcinoma Pulmonar de Células não Pequenas/patologia , Terapia Neoadjuvante , Carcinoma Adenoescamoso/tratamento farmacológico , Carcinoma Adenoescamoso/genética , Receptores ErbB/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Pulmão/patologia , Mutação
7.
Chirality ; 36(1): e23619, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37700546

RESUMO

Even though chiral recognition for crown-ether CSPs is generally understood, on a molecular level, exact mechanisms for the resolution are still unclear. Furthermore, short peptide analytes often contain multiple amino moieties capable of binding to the crown ether selector. In order to extend the understanding in chiral recognition mechanisms, polar organic mode separation of Tyr-Arg-Phe-Lys-NH2 tetrapeptide llll/dddd enantiomers on S- and R-(3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 stationary phases was studied with 50-mM perchloric acid in methanol as mobile phase. Deviation from the generally acceptable 1:1 stoichiometry was supported by mass spectroscopy analysis of the formed complexes between tetrapeptide enantiomer and crown ether selectors, which revealed adducts possessing 1:1, 1:2, and 1:3 stoichiometry. Further investigation of complexation induced shifts by NMR indicated on different binding mechanisms between llll/dddd enantiomers of Tyr-Arg-Phe-Lys-NH2 and crown ether selectors. Enantioselective proton shifts were observed in studied tetrapeptide tyrosine and phenylalanine residues exclusively for llll enantiomer upon binding with S-(3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 selector (and dddd enantiomer with R-(3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 selector), indicating that these two amino acid residues contribute to chiral recognition. The obtained results were in agreement with the LC data.


Assuntos
Éteres de Coroa , Éteres de Coroa/química , Estereoisomerismo , Tirosina , Fenilalanina , Cromatografia Líquida de Alta Pressão/métodos
8.
Bioconjug Chem ; 35(1): 22-27, 2024 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-38086083

RESUMO

The Sulfo-NHS ester is a mainstay reagent for facilitating amide bond formation between carboxylic acids and amine functionalities in water. However, the preparation of Sulfo-NHS esters currently requires hydrophobic carboxylic acids, which are poorly water-soluble, to first be reacted with the N-hydroxysulfosuccinimide sodium salt, which is insoluble in organic solvents. The mutually incompatible solvation requirements thus complicate the synthesis of Sulfo-NHS esters. As a simple, rapid, and cost-effective solution to this problem, we report that the use of 15-crown-5 to complex the sodium cation of N-hydroxysulfosuccinimide sodium salt circumnavigates these solvation incompatibility issues by rendering the N-hydroxysulfosuccinimide salt soluble in organic solvents, resulting in a cleaner esterification reaction and thus improved yields of activated ester product. We also demonstrate that the resultant "crowned" Sulfo-NHS-ester remains water-soluble and is no less reactive than its classic "uncrowned" Sulfo-NHS counterpart when used in bioconjugation reactions between protein amine-functionalities and hydrophobic carboxylic acids.


Assuntos
Éteres de Coroa , Ésteres , Succinimidas , Água , Solubilidade , Solventes/química , Proteínas , Aminas , Sódio
9.
J Sep Sci ; 46(22): e2300520, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37775313

RESUMO

The purity analysis of therapeutic peptides can often be challenging, demanding the application of more than a single analytical technique. Supercritical fluid chromatography nowadays is a promising alternative to reversed-phase liquid chromatography, providing orthogonal and complementary information. This study investigated its applicability for the separation of human insulin, its analogs and degradation products. A previously published method development protocol for peptides up to 2000 Da was successfully applied to the higher molecular weight insulins (6 kDa). A single gradient method was optimized for all insulins using a Torus DEA column (100 × 3.0 mm, 1.7 µm), carbon dioxide and a modifier consisting of methanol/acetonitrile/water/methanesulfonic acid (65:35:2:0.1, v/v/v/v). Consecutively, the crown ether 18-crown-6, which is well known to complex charged lysine sidechains and other amino functionalities, was added to the modifier to evaluate its impact on selectivity. A decreased retention and a shift in the elution order for the insulins were observed. An inverse effect on retention was found when combined with a neutral stationary phase chemistry (Viridis BEH).


Assuntos
Cromatografia com Fluido Supercrítico , Éteres de Coroa , Humanos , Insulina , Cromatografia com Fluido Supercrítico/métodos , Metanol/química , Dióxido de Carbono/química
10.
Chirality ; 35(12): 966-972, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37464950

RESUMO

Considering the greater pharmaceutical and clinical interest of triiodothyronine (T3 ) thyroid hormone, an effective D/L-T3 enantiomer separation was performed on a crown ether-based chiral stationary phase by LC-MS/MS. In optimal analytical condition and selected reaction monitoring mode, the two enantiomers of T3 were baseline separated within 10 min. The limit of detection and limit of quantitation were found to be 0.05 and 0.10 ng/µl; 0.20 and 0.50 ng/µl for D- and L-T3 , respectively. During validation, this method proved to be feasible, accurate as well as enantioselective and sensitive for the resolution of T3 enantiomers. For commercial D- and L-T3 chemicals, the enantiomeric impurities as the other enantiomer were 0.11% and 4.61%. On the other hand, the impurity as D-T3 for commercial pharmaceutical products (liothyronine sodium tablets, two suppliers) was 0.68% and 6.57%.


Assuntos
Éteres de Coroa , Tri-Iodotironina , Cromatografia Líquida , Estereoisomerismo , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão/métodos
11.
Int J Mol Sci ; 24(10)2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37240291

RESUMO

The aim of the work was to analyze the preferential solvation process, and determine the composition of the solvation shell of cyclic ethers using the calorimetric method. The heat of solution of 1,4-dioxane, 12-crown-4, 15-crown-5 and 18-crown-6 ethers in the mixture of N-methylformamide with water was measured at four temperatures, 293.15 K, 298.15 K, 303.15 K, and 308.15 K, and the standard partial molar heat capacity of cyclic ethers has been discussed. 18-crown-6 (18C6) molecules can form complexes with NMF molecules through the hydrogen bonds between -CH3 group of NMF and the oxygen atoms of 18C6. Using the model of preferential solvation, the cyclic ethers were observed to be preferentially solvated by NMF molecules. It has been proved that the molar fraction of NMF in the solvation shell of cyclic ethers is higher than that in the mixed solvent. The exothermic, enthalpic effect of preferential solvation of cyclic ethers increases with increasing ring size and temperature. The increase in the negative effect of the structural properties of the mixed solvent with increase in the ring size in the process of preferential solvation of the cyclic ethers indicates an increasing disturbance of the mixed solvent structure, which is reflected in the influence of the energetic properties of the mixed solvent.


Assuntos
Éteres de Coroa , Água , Temperatura , Água/química , Éteres Cíclicos , Éteres de Coroa/química , Solventes
12.
Angew Chem Int Ed Engl ; 62(26): e202304083, 2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37114678

RESUMO

The dynamic covalent chemistry (DCvC) of the Si-O bond holds unique opportunities, but has rarely been employed to assemble discrete molecular architectures. This may be due to the harsh conditions required to initiate exchange reactions at silicon in aprotic solvents. Herein, we provide a comprehensive experimental and computational account on the reaction of trialkoxysilanes with alcohols and identify mild conditions for rapid exchange in aprotic solvents. Substituent, solvent and salt effects are uncovered, understood and exploited for the construction of sila-orthoester cryptates. A sharp, divergent pH-response of the obtained cages renders this substance class attractive for future applications well beyond host-guest chemistry, for instance, in drug delivery.


Assuntos
Éteres de Coroa , Sistemas de Liberação de Medicamentos , Silício , Solventes , Concentração de Íons de Hidrogênio
13.
Chemistry ; 29(25): e202300044, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-36723493

RESUMO

Bilayer membranes that enhance the stability of the cell are essential for cell survival, separating and protecting the interior of the cell from its external environment. Membrane-based channel proteins are crucial for sustaining cellular activities. However, dysfunction of these proteins would induce serial channelopathies, which could be substituted by artificial ion channel analogs. Crown ethers (CEs) are widely studied in the area of artificial ion channels owing to their intrinsic host-guest interaction with different kinds of organic and inorganic ions. Other advantages such as lower price, chemical stability, and easier modification also make CE a research hotspot in the field of synthetic transmembrane nanopores. And numerous CEs-based membrane-active synthetic ion channels were designed and fabricated in the past decades. Herein, the recent progress of CEs-based synthetic ion transporters has been comprehensively summarized in this review, including their design principles, functional mechanisms, controllable properties, and biomedical applications. Furthermore, this review has been concluded by discussing the future opportunities and challenges facing this research field. It is anticipated that this review could offer some inspiration for the future fabrication of novel CEs-derived ion transporters with more advanced structures, properties, and practical applications.


Assuntos
Éteres de Coroa , Nanoporos , Éteres de Coroa/química , Canais Iônicos/química , Íons
14.
Int J Biol Macromol ; 230: 123162, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36623620

RESUMO

Due to its inherent properties and wide availability, cellulose acetate is an extremely competitive candidate for the production of polymeric membranes. However, for best results in particular applications, membrane modification is required in order to minimize unwanted interactions and introduce novel characteristics to the pristine polymer. In this study, the surface of commercial cellulose acetate membranes was functionalized with 4'-aminobenzo-15-crown-5 ether, using a covalent bonding approach. The main goal was the improvement of the membranes biomineralization ability, thus making them prospective materials for bone regeneration applications. The proposed reaction mechanism was confirmed by XPS and NMR analysis while the presence of the functionalization agents in the membranes structure was showed by ATR FT-IR and Raman spectra. The effects of the functionalization process on the morphology, thermal and mechanical properties of the membranes were studied by SEM, TGA and tensile tests. The obtained results revealed that the cellulose acetate membranes were successfully functionalized with crown ether and provided a good understanding of the interactions that took place between the polymer and the functionalization agents. Moreover, promising results were obtained during the Taguchi biomineralization studies. SEM images, EDX mapping and XRD spectra indicating that the CA-AB15C5 membranes have a superior Ca2+ ions retention ability, this causing an accentuated calcium phosphate deposition on the modified polymeric fibers, compared to the neat CA membrane.


Assuntos
Éteres de Coroa , Osseointegração , Espectroscopia de Infravermelho com Transformada de Fourier , Polímeros/química , Membranas Artificiais
15.
Int J Biol Macromol ; 231: 123200, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36634801

RESUMO

In this work, we synthesized cryptate copper(II) followed by complexed with sulfonate chitosan (SCS). After characterization, the evaluation of the antioxidant properties of resulting complexes were carried out by 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH•), hydroxyl radical (•OH), and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS•+), while the antibacterial and biofilm inhibitory activity against Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1) were also investigated. According to the results, cryptate copper(II) exhibited the best antioxidant activity followed by cryptate copper(II)/SCS complexes, and SCS. Significant antibacterial activity of cryptate copper(II) against P. aeruginosa PAO1 was observed with the minimum inhibitory concentration of MIC value 12.50 µg/mL and minimum bactericidal concentration of MBC value 100.00 µg/mL, followed by cryptate copper(II)/SCS complexes and SCS. Cryptate copper(II) and cryptate copper(II)/SCS exhibited antibacterial activity which copper ions might enter the interior of cells, and the intracellular ions made the killed bacteria serve as an antibacterial agent showing a zombie effect. The copper ions complexed with cryptate and SCS rendering potential unlimited biological activities, might become one of the most popular research areas because of their unique coordination chemistry and their long-term biological activities.


Assuntos
Quitosana , Éteres de Coroa , Antioxidantes/química , Cobre/química , Quitosana/química , Pseudomonas aeruginosa , Alcanossulfonatos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana
16.
Zhonghua Zhong Liu Za Zhi ; 45(1): 31-38, 2023 Jan 23.
Artigo em Chinês | MEDLINE | ID: mdl-36709117

RESUMO

Clinical studies have established the clinical application of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) adjuvant targeted therapy. Compared with chemotherapy, the high efficiency and low toxicity of targeted therapy increases the survival benefit of patients. Icotinib was the first EGFR-TKI with independent intellectual property rights in China and the third EGFR-TKI to be marketed in the world. In order to summarize the experience of icotinib and other EGFR-TKIs in the adjuvant treatment of non-small cell lung cancer and further standardize and guide the clinical application of icotinib, experts from the China International Exchange and Promotive Association for Medical and Health Care and the Guangdong Association of Thoracic Diseases have organized an expert consensus on the adjuvant treatment of non-small cell lung cancer with icotinib, which is expected to provide clinicians with evidence-based medical evidences for postoperative targeted drug using.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Éteres de Coroa , Neoplasias Pulmonares , Humanos , Neoplasias Pulmonares/cirurgia , Consenso , Mutação , Receptores ErbB/genética , Éteres de Coroa/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico
17.
Analyst ; 148(2): 344-353, 2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36533333

RESUMO

Urinary potassium is an important parameter in clinical health diagnosis. Rapid and convenient detection of potassium ions (K+) in urine is essential for personal healthcare and health management. Here, crown ether (4-aminodibenzo-18-crown-6, ADC) modified silver nanoparticles (ADC-Ag NPs) were successfully prepared for one-step rapid colorimetric detection of urinary potassium. The detection mechanism is as follows: due to the matching sizes of the diameter of K+ and the cavity in crown ether 6, K+ is encapsulated between the cavities of two crown ethers, resulting in the clumping of ADC-Ag NPs and the color of the solution being altered. The colorimetric detection method has a fast response and is completed within 20 minutes. It also shows good selectivity and interference immunity. The lowest detectable concentration is 20 µM with the naked eye and 2.16 µM for UV-vis absorption spectroscopy. A good linear relationship (R2 = 0.9931) between the absorption intensity ratio and K+ concentration (0-100 µM) indicates that this colorimetric probe can be used to detect K+. The method was also applied for quantitative analysis of K+ in real urine samples with recovery between 116 and 120%.


Assuntos
Éteres de Coroa , Nanopartículas Metálicas , Nanopartículas Metálicas/química , Prata/química , Colorimetria/métodos , Espectrofotometria Ultravioleta/métodos , Íons
18.
J Am Chem Soc ; 145(2): 1285-1291, 2023 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-36584399

RESUMO

Maintaining the protein high-order structures and interactions during the transition from aqueous solution to gas phase is essential to the structural analysis of native mass spectrometry (nMS). Herein, we systematically interrogate the effects of charge state and crown ether (CE) complexation on the gas-phase native-like protein structure by integrating nMS with 193 nm ultraviolet photodissociation (UVPD). The alterations of photofragmentation yields of protein residues and the charge site distribution of fragment ions reveal the specific sites and sequence regions where charge and CE take effect. Our results exhibit the CE complexation on protonated residues can largely alleviate the structure disruption induced by the intramolecular solvation of charged side chains. The influences of CE complexation and positive charge on gas-phase protein structure exhibit generally opposite trends because the CE microsolvation avoids the hydrogen-bonding formation between the charged side chains with backbone carbonyls. Thus, CE complexation leads to a more stable and native-like protein structure in the gas phase.


Assuntos
Éteres de Coroa , Éteres de Coroa/química , Proteínas/química , Espectrometria de Massas , Íons , Água , Raios Ultravioleta
19.
J Hazard Mater ; 444(Pt B): 130437, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36436388

RESUMO

Technetium-99m (99mTc) is an important medical radionuclide. Due to the crisis in supply of molybdenum-99 (99Mo), production of 99mTc directly via the 100Mo (p, 2 n) reaction by cyclotron was proposed. In this process, the most critical challenge is to rapidly and efficiently separate 99mTc from high concentration of molybdenum. In this work, a novel ligand, bis(N,N-dibutyldiglycolamide)dibenzo-18-crown-6 (BisDBDGA-DB18C6) was successfully synthesized and used for extraction of TcO4- /ReO4- from molybdenum. The results demonstrated that BisDBDGA-DB18C6 expressed excellent selectivity for TcO4- with a high separation factor of 1.6 × 105 against Mo, a fast extraction kinetic (within 45 s), and a high extraction capacity of 211 mmol ReO4- (99TcO4-)/per mole of extractant. The extraction mechanism was proposed as a co-interaction of macrocyclic crown ether and N,N-dibutyldiglycolamide group through slope analysis, FT-IR, ESI-MS, 1H NMR titration and theory calculations. Importantly, 99Tc in the organic phase can be quantitatively (> 99%) and easily back-extracted using deionized water, which can be directly used for medical applications.


Assuntos
Éteres de Coroa , Molibdênio , Espectroscopia de Infravermelho com Transformada de Fourier , Cinética , Água
20.
J Hazard Mater ; 443(Pt B): 130268, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36327830

RESUMO

Microporous organic networks (MONs) are a booming class of functional materials in elimination of environmental pollutants. However, the limit varieties of MONs still restrict their broad applications. Here we report the synthesis of a novel type of crown ether (CE)-based MONs via the coupling between brominated 18-crown-6 ether and different aromatic alkynyls. The constructed CE-based MONs integrates the good conjugation property of MONs and the inherent host-guest binding sites of CE, allowing the ultrafast and efficient adsorption and removal of a typical environmental priority pollutant 2,4,6-trichlorophenol (2,4,6-TCP). The hydrophobic CE-based MONs can also address the recovery challenge of unstable discrete CE in most organic and inorganic solvents. All CE-based MONs displayed fast adsorption kinetics (< 3 min) and large adsorption capacities (229.1-341.7 mg g-1) for 2,4,6-TCP. The CE-based MONs also gave stable adsorption capacities for 2,4,6-TCP in pH range of 4.0-6.0, NaCl concentration of 0-40 mg L-1, HA concentration of 0-30 mg L-1, or H2O2 ratio of < 5 %. Density functional theory calculation, Fourier transform infrared and X-ray photoelectron spectra evaluation revealed adsorption process involved hydrophobic, π-π and hydrogen bonding interactions. The CE-based MONs also showed favorable reusability and good adsorption for other toxic chlorophenols. This work highlights the potential of CE-based MONs in contaminants elimination.


Assuntos
Clorofenóis , Éteres de Coroa , Poluentes Ambientais , Poluentes Químicos da Água , Clorofenóis/química , Peróxido de Hidrogênio , Adsorção , Poluentes Ambientais/química , Poluentes Químicos da Água/análise
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